From the archives of Bob Montgomery, motoring historian
PROPELLER-DRIVEN CARS: Yes, today the very notion of a propeller-driven car seems daft. But in 1919, when French pioneer aviator Marcel Leyat built an estimated 30 such cars, it seemed to many that there was considerable merit in the idea.
Indeed there was a certain logic behind Leyat's voiture à hélice. Conventional cars of the time lost as much as 46 per cent of their power through transmission losses. Leyat realised that with a propeller-driven car, this fell below 30 per cent, because no gearbox or transmission of any sort was required.
In addition a propeller-driven car was mechanically much simpler - and thus likely to be more reliable at a time when reliability was a major issue for buyers. Finally, because the whole car was simpler, weight and the cost of manufacture both fell.
Oddly enough, Leyat wasn't the only inventor who conceived of a propeller-driven car. Several others were built as prototypes but Leyat's - and this was the essential difference - conceived of his as a complete design, rather than just a car which had been fitted with an engine and propeller.
As a result Leyat's design had its propeller in the nose of an aerodynamically designed aircraft-style plywood monocoupe, giving a lightweight, rigid and economical structure.
Leyat went further. Following aircraft practice he steered the Hélice from the rear. His reason for doing so was that it was simpler and made the car less vulnerable to front-end damage.
Leyat also believed that rear brakes induced skids and with a rear-steering layout he could retain brakes on the front alone. The result was capable of a claimed 50 mph from its 8hp air-cooled V-twin engine and had a petrol consumption of 70mpg. Leyat claimed the Hélice would be ideal for use in the French colonies where its light weight would give it an advantage over surfaces such as loose sand.
By 1921 Leyat claimed to have 600 orders, including one from the King of Spain but by 1923 the Leyat works was at a total standstill. Leyat, it seems, had sold the manufacturing rights for France and the French colonies to a Mr Archer.
Archer changed the design, most notably by the introduction of front-wheel steering, and this outraged Leyat, leading to a law-case between the two men.
In 1924 Leyat regained control of his patents and in 1927, in an effort to relaunch manufacture of his propeller-driven car, he took a specially built Hélice to the banked circuit at Montlhéry. There he achieved a run of 106mph and a fuel consumption of 47mpg with an 8hp engine.
But by now advances in more conventional cars had overtaken Leyat's ideas, and the momentum which had been built up for sales of the Hélice was forever lost. As a result Leyat turned his attention to designing a lightweight plane, and the Hélice was consigned to become a footnote in automobile history.
Just two survive today - testimony to one man's original thinking - for today lightweight monocoupes and aerodynamic efficiency are things we take for granted, but whose importance Marcel Leyat fully understood as long ago as 1919.